I have to say the best advice I've received so far with respect to etching circuit boards came from Tony Nixon. I heat my etchant by putting my etching tray in a sink of warm water, I use a small paint brush and I brush the circuit board while it is in the etchant (gently brushing away the copper). This changed my etching time from about 25 minutes using room temp etchant and agitation to about 3 minutes with warm etchant and a brush. Regards Stuart O'Reilly ----- Original Message ----- From: Jinx To: Sent: Saturday, July 15, 2000 8:30 AM Subject: Re: [EE]: PCBs using toner transfer paper > > Mitchell D. Miller wrote: > > > > > light. Exposure and development of the board went fine ... etching was > > > quite slow because I didn't keep my etchant (ferric chloride) warm. As > > > > My lowest-budget trick here: I use a Rubbermaid low rectangular plastic > > container to etch in - I fill the sink with HOT water, about 5 minutes > > early - then drop the board into that hot ferric chloride once it's > > warm. Works pretty well. Don't over-fill the plastic container with > > etchant! > > > > Mark > > To get away from the sink and serious assault if FeCl gets anywhere > it shouldna, I use a 1 litre container inside a 2 litre and peg them at the > top edge. Fill the 2l with hot water from the kettle to match the level of > the FeCl in the 1l. Then float the board upside-down on top of the FeCl. > There's enough surface tension to do this if you're careful. And once the > Cu starts coming off, the board becomes lighter. I've found this etches > much faster even without agitation (ie you can go clean up the mess > you left behind drawing up the board) than letting the board languish at > the bottom facing up. Probably because the dirty etchant drops away from > the Cu and doesn't just pool up on it. With most grp board the contrast > between dark FeCl and the etched pattern is good enough to see thru > the board, and I have a pair of plastic tongs to check after 5 minutes. It > can be put back on the surface quite easily. The only caveat is that the > FeCl must be decanted from it's bottle fairly carefully to stop too much > scum floating on the surface. However, the small amount that does re- > dissolves once the FeCl heats up. Bubbles under the board is rarely a > problem once you have the knack of sliding it on the surface. Lifting > it by one end and then putting it back down drives any bubbles out, if > they were there in the first place, which they usually aren't. Mostly I'd > only use 1/2" of FeCl, the less the better for taking heat away from > the hot water, and it'll stay very hot for the 7-10 minutes etching time > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.